Spring 2011 hit the rear view mirror at 12:16 p.m. Tuesday and I'm guessing many were ready to see it go.

Generally cool and wet, this year's spring failed miserably in living up to the expectations of most. Perhaps the most strange occurrence in the unseasonably cool season was that Mother Nature somehow managed to mix in three straight days of record highs in the 90s.

Summer 2011 begins with dripping humidity. Many may choose to run air conditioners not because it's warm, but simply to squeeze some of the dampness out of the house.

Meanwhile, it will remain plenty damp outside as there will be periods of rain and thunderstorms Tuesday, Wednesday and Thursday. Storms on Tuesday and Tuesday night could be very heavy and may lead to trouble for those in flood-prone areas.

Within two days of the start of summer, temperatures will nose-dive. Unseasonably cool highs in the 60s are expected both Thursday and Friday. The normal high is 79. Highs will slowly moderate back into the 70s over the weekend.

There is reason for great optimism about the weather beginning next week and all the way through the weekend of the 4th of July.

Not only does it look like a drier stretch of weather, but a big warm-up appears to be in the cards. Indications are we'll have an extended stretch of days with highs in the 80s beginning in true middle of next week. Plus, readings at or above 90 aren't off the table for the 4th of July weekend.

When the sirens sounded Wednesday night in Waukesha, most who heard them assumed a tornado warning had been issued. Residents of Muskego and Kenosha heard similar sirens and also assumed that a tornado was threatening.

Nope.

It turns out the sirens were sounded in those communities (and others) because of the potential for destructive, non-tornado winds.

But wait, you say, they are "tornado sirens." Aren't they supposed to be used for tornadoes only?

Not necessarily.

I'm told that many local communities reserve the right to sound their sirens for any situation that may be considered a serious threat to public safety. In the case of Wednesday night, the National Weather Service was warning about the potential for winds over 100 miles per hour. Winds of that strength are strong enough to do major to damage to homes, power lines, trees, etc. In my estimation, 100 mph winds do qualify as a serious threat to public safety.

But wait, you say, if the winds are going to be over 100 mph, there has to be a tornado, right?

Not true.

When certain atmospheric conditions are in place, wind speeds can hit triple digits without the presence of a tornado. We call these "straight-line" winds, as opposed to the rotating winds of a tornado. This type of situation isn't common, but it does happen more often than you might think.

And here's the kicker: What many don't realize is that a large percentage of tornadoes barely get much over 100 mph.

So, in the case of Wednesday night, we had a situation where the potential for damage was about equal to that in most tornado situations. Therefore, officials in many communities determined that the situation was serious enough to sound their warning sirens.

Some communities remained silent. Some may not have deemed the potential for 100-plus mph winds siren-worthy. Others may have a policy that they only hit the horn for official tornado warnings. There may have been other reasons as well.

It is likely the record book will be re-written again on Wednesday as Milwaukee experiences a third straight day of blistering heat.

Milwaukee's high temperature on Wednesday is expected to be in the low to mid-90s. The record high is a very reachable 93 degrees, set in 1933.

The heat index, a measure of how hot it really feels when relative humidity is factored with the actual air temperature, will top out in the mid to upper 90s.

As Wednesday afternoon turns to evening, the searing heat may be broken by powerful thunderstorms. A cold front will barrel across Wisconsin early Wednesday night and break the three-day heat wave. Before the front passes, thunderstorms with damaging winds and hail are possible.

After the front passes, there will be a whiplash-inducing cool down. Temperatures on Thursday will be 30 degrees cooler with highs only in the 60s. Two more days in the 60s are likely to follow on Friday and Saturday.

The high temperatures of 94 on Monday and 97 on Tuesday broke records that had stood for 86 and 78 years, respectively. The highest June temperature on record in Milwaukee occurred on June 1, 1934 when the mercury hit 104 degrees.

Remember when we were suffering through that seemingly endless stretch of chilly weather in April and May? Yeah, that's over.

A brief, yet blistering heat wave is underway.

Monday's high temperatures in the 90s will be repeated again both Tuesday and Wednesday.

The official high temperature in Milwaukee on Monday was 94 degrees. That broke an 86-year-old record for the top temperature ever recorded on June 6.

Expect the record book to again be rewritten Tuesday and Wednesday, with highs of 95 and 93 degrees, respectively.

While readings on area thermometers soar into the mid-90s, the heat index will be around 100. The heat index, sometimes referred to as "apparent temperature," is a measure of how hot it really feels when relative humidity is factored with the actual air temperature.

The average high for this time of the year is usually in the mid 70s. The highest June temperature on record in Milwaukee occurred June 1, 1934 when the mercury hit 104 degrees.

Temperatures tumble back to more reasonable level Thursday with highs in the 70s. It will be cooler still on Friday with highs in the 60s.

About Craig Koplien

Craig is a meteorologist who was born and raised in Pewaukee. After getting a degree in Meteorology from the University of Wisconsin-Madison, he worked over 20 years on TV and radio in Milwaukee, Madison, Omaha, Nebraska and Kansas City, Missouri.

Craig spends most of his time trying to keep up with his bride and their three teenage daughters. Any time left over is spent with his other beloveds, the Packers, Brewers and Badgers.